When turbines, in particular steam turbines, start up, an excessively rapid rise in temperature has to be avoided in order to avoid damage to the components. Therefore, the temperatures of components which are subjected to thermal stress are monitored. If the temperatures or the rise in temperature exceeds a setpoint value, a controller of the turbine power level is acted on to stop the increase in power. In some cases this results in delays during the starting of the turbine.
GB 2 074 757 A presents a method and an arrangement for controlling the thermal stress of components of a steam turbine at maximum load rates and load-relief rates during the running up, deactivation and other periods of the change in load. A load rate for each of a plurality of preselected turbine components is calculated from monitored and derived variables, and the lowest rate is selected for the control. At the same time, the steam action operating mode of the turbine is directed automatically either to the partial arc operating mode or the full arc operating mode, depending on the need to reduce the stress.
U.S. Pat. No. 4,208,060 A presents a monitoring control system for a steam turbine generator having a hierarchy of microcomputer partial systems which cooperate interactively with a conventional analog electrohydraulic control system in order to permit control and monitoring during all the operating phases of the turbine generator.
US 2006/233637 A1 presents a turbine start controller with an optimum start control unit for predicting thermal stress which is determined into the future in a turbine rotor during a prediction period on the basis of the current time, wherein a turbine acceleration rate and a load increase rate are used as control variables.
U.S. Pat. No. 5,044,152 A presents a method for operating a combined power plant with a gas turbine system and an evaporator in which steam is generated from the heat of the turbine exhaust gases and fed to a steam turbine which is operated by the steam which is generated in this way. An inlet into the gas turbine system is controlled on the basis of the state of the evaporator or of the steam turbine.